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+--- Thread: Sharpening text in a jpg image (/Thread-Sharpening-text-in-a-jpg-image)
Sharpening text in a jpg image - PAL Thai - 01-15-2019
[attachment=2488]
Hi! I'm quite new to GIMP and would like to make use of its capabilities as follows:
I have a .jpg image of an outdoor sign that when zoomed to 400% shows the white text of the sign quite blurred. I am hoping to find the proper way to sharpen and whiten just the white text and leave everything else on the image as it is, i.e. slightly blurred. I have attached the file in question so you can see for yourself what I am talking about. The border and empty space surrounding the image must remain as seen so as to have the correct size for posting to a Yahoo! Page. Many thanks to those members who may help me out.
RE: Sharpening text in a jpg image - rich2005 - 01-15-2019
Lots of jpeg artefacts. The image maybe exported at low quality / scaled up from a tiny image.
Try:
1. Duplicate the image layer Layer -> Duplicate Layer and in the new top layer use the Threshold tool Colors -> Treshold Move the center slider a little to the left to make white areas whiter.
2. Paint out in black all of the background leaving the text.
screenshots https://i.imgur.com/vu0xF3F.jpg
3. Apply a small (values = 3) Gaussian Blur Filters -> Blur -> Gaussian Blur
4. In the layers dialogue change the mode of the top layer to Screen
5. Exporting as a new jpeg? Untick all the exif stuff. Do you need that comment? Otherwise default values give a file size much the same as the original.
screenshots https://i.imgur.com/ujAUYSo.jpg
edit: I wish I could give some simple way to improve that overall. Guessing at much of the jpeg artefacts actually come from over-sharpening. A partial reconstruction, scale the image up 400% then clean up, scale back down to original size, new borders to finish. Not a quick process. Gets this.
[attachment=2489]
RE: Sharpening text in a jpg image - PAL Thai - 01-17-2019
(01-15-2019, 09:01 AM)rich2005 Wrote: Lots of jpeg artefacts. The image maybe exported at low quality / scaled up from a tiny image.
Try:
1. Duplicate the image layer Layer -> Duplicate Layer and in the new top layer use the Threshold tool Colors -> Treshold Move the center slider a little to the left to make white areas whiter.
2. Paint out in black all of the background leaving the text.
screenshots https://i.imgur.com/vu0xF3F.jpg
3. Apply a small (values = 3) Gaussian Blur Filters -> Blur -> Gaussian Blur
4. In the layers dialogue change the mode of the top layer to Screen
5. Exporting as a new jpeg? Untick all the exif stuff. Do you need that comment? Otherwise default values give a file size much the same as the original.
screenshots https://i.imgur.com/ujAUYSo.jpg
edit: I wish I could give some simple way to improve that overall. Guessing at much of the jpeg artefacts actually come from over-sharpening. A partial reconstruction, scale the image up 400% then clean up, scale back down to original size, new borders to finish. Not a quick process. Gets this.
Many thanks for the suggestions and a peek at the finished product. I will print out your post and use its contents as I try my hand at sharpening the white text of the jpg in question.
I'll keep my fingers crossed as I move through the steps since I'm quite new to GIMP. But the last picturein your post really does sharpen the white text and makes it very legible indeed.